Previous Year Questions
86 questions — organised by subject with solutions and explanations.
🎯 Practice smarter, not harder
Just sign in to unlock everything. Free for all students.
Choose the correct match for input resistance of various amplifier configurations shown below :
If the op-amp in the figure is ideal, the output voltage will be equal to
If the input to the ideal comparators shown in the figure is a sinusoidal signal of 8 V (peak to peak) without any DC component, then the output of the comparators has a duty cycle of
If the differential voltage gain and the common mode voltage gain of a differential amplifier are 48 dB and 2 dB respectively, then common mode rejection ratio is
Three identical amplifiers with each one having a voltage gain of 50, input resistance of 1 k and output resistance of 250 are cascaded. The opened circuit voltages gain of the combined amplifier is
The action of JFET in its equivalent circuit can best be represented as a
The circuit shown in the figure is best described as a
The output voltage of the regulated power supply shown in the figure is
An amplifier without feedback has a voltage gain of 50, input resistance of 1 k and output resistance of 2.5 k . The input resistance of the current-shunt negative feedback amplifier using the above a
In the amplifier circuit shown in the figure, the values of and are such that the transistor is operating at = 3 V and = 1.5 mA when its is 150. For a transistor with of 200, the operating point ( , )
Generally, the gain of a transistor amplifier falls at high frequencies due to the
The oscillator circuit shown in the figure has an ideal inverting amplifier. Its frequency of oscillation (in Hz) is
A superheterodyne receiver is to operate in the frequency range 550 kHz - 1650 kHz, with the intermediate frequency of 450 kHz. Let R = denote the required capacitance ratio of the local oscillator an
At a given probability of error, binary coherent FSK is inferior to binary coherent PSK by.
Let be the message signal & be the carrier. c(t) and m(t) are used to generated an FM signal. If the peak frequency deviation of the generated FM signal is three times the transmission bandwidth of th
A sinusoidal signal with peak-to-peak amplitude of 1.536 V is quantized into 128 levels using a mid-rise uniform quantizer. The quantization-noise power is
If S represents the carrier synchronization at the receiver and represents the bandwidth efficiency, then the correct statement for the coherent binary PSK is
X(t) is a random process with a constant mean value of 2 and the auto correlation function . Let Y and Z be the random variable obtained by sampling X(t) at t=2 and t=4 respectively. Let W=Y-Z. The va
Let be the message signal and be the carrier. c(t) and m(t) are used to generate an AM signal. The modulation index of the generated AM signal is 0.5. Then the quantity is
Let X and Y be two statistically independent random variables uniformly distributed in the ranges (-1,1) and (-2,1) respectively. Let Z=X+Y. Then the probability that (Z -1) is
Choose the correct one from among the alternative A,B,C,D after matching an item in Group 1 with most appropriate item in Group 2.
A DSB-SC signal is to be generated with a carrier frequency = 1 MHz using anon-linear device with the input-output characteristic where and are constants. The output of the non-linear device can be fi
The input to a linear delta modulator having a step-size =0.628 is a sine wave with frequency and peak amplitude . If the sampling frequency =40 kHz, the combination of the sine-wave frequency and the
If , the energy per bit of a binary digital signal, is watt-sec and the one-sided power spectral density of the white noise, W/Hz, then the output SNR of the matched filter is
A signal is sampled at 8 kHz and is quantized using 8-bit uniform quantizer. Assuming SNRq for a sinusoidal signal, the correct statement for PCM signal with a bit rate of R is
The noise at the input to an ideal frequency detector is white. The detector is operating above threshold. The power spectral density of the noise at the output is
The input to a coherent detector is DSB-SC signal plus noise. The noise at the detector output is
The root locus of system has the break-away point located at
Fig. shows the Nyquist plot of the open-loop transfer function G(s)H(s) of a system. If G(s)H(s) has one right-hand pole, the closed-loop system is
A second-order system has the transfer function . With r(t) as the unit-step function, the response c(t) of the system is represented by
The zero-input response of a system given by the state-space equation and is
The signal flow graph of a system is shown in Fig. below. The transfer function C(s)/R(s) of the system is
The gain margin and the phase margin of feedback system with are
The approximate Bode magnitude plot of a minimum phase system is shown in Fig. below. The transfer function of the system is
A PD controller is used to compensate a system. Compared to the uncompensated system, the compensated system has
A 0 to 6 counter consists of 3 flip flops and a combination circuit of 2 input gate(s). The common circuit consists of
The minimum number of comparators required to build an 8-bits flash ADC is
The number of distinct Boolean expressions of 4 variables is
The circuit in the figure has 4 boxes each described by inputs P,Q,R and outputs Y,Z with Y = and The circuit acts as a
The circuit shown in figure converts
The output of the 74 series of GATE of TTL gates is taken from a BJT in
If the function W,X,Y and Z are as follows , , , Then,
The DTL, TTL, ECL and CMOS famil GATE of digital ICs are compared in the following 4 columns The correct column is
Without any additional circuitry, an 8:1 MUX can be used to obtain
A 4 bit ripple counter and a bit synchronous counter are made using flip flops having a propagation delay of 10 ns each. If the worst case delay in the ripple counter and the synchronous counter be R
In the circuit shown in the figure, A is parallel-in, parallel-out 4 bit register, which loads at the rising edge of the clock C . The input lines are connected to a 4 bit bus, W. Its output acts at i
The circuit shown in the figure is a 4 bit DAC The input bits 0 and 1 are represented by 0 and 5 V respectively. The OP AMP is ideal, but all the resistance and the 5 v inputs have a tolerance of 10%.
If the electric field intensity is given by volt/m, the potential difference between X(2,0,0) and Y(1,2,3) is
A uniform plane wave traveling in air is incident on the plane boundary between air and another dielectric medium with = 4. The reflection coefficient for the normal incidence, is
If the electric field intensity associated with a uniform plane electromagnetic wave traveling in a perfect dielectric medium is given by V/m, then the velocity of the traveling wave is
The unit of is
Medium 1 has the electrical permittivity farad/m and occupies the region to the left of x = 0 plane. Medium 2 has the electrical permittivity farad/m and occupies the region to the right of x = 0 plan
A short - circuited stub is shunt connected to a transmission line as shown in fig. If = 50 ohm, the admittance Y seen at the junction of the stub and the transmission line is
The depth of penetration of electromagnetic wave in a medium having conductivity at a frequency of 1 MHz is 25 cm. The depth of penetration at a frequency of 4 MHz will be
A rectangular metal wave guide filled with a dielectric material of relative permittivity = 4 has the inside dimensions 3.0 cm 1.2 cm. The cut-off frequency for the dominant mode is
The Bandgap of silicon at 300 K is
An n-type silicon bar 0.1 cm long and 100 in cross-sectional area has a majority carrier concentration of and the carrier mobility is 0.13 at 300 K. If the charge of an electron is coulomb, then the r
Choose proper substitutes for X and Y to make the following statement correct Tunnel diode and Avalanche photo diode are operated in X bias ad Y bias respectively
The electron concentration in a sample of uniformly doped n-type silicon at 300 K varies linearly from at x = 0 to at x = 2 . Assume a situation that electrons are supplied to keep this concentration
Match items in Group 1 with items in Group 2, most suitably.
n-type silicon is obtained by doping silicon with
For an n - channel enhancement type MOSFET, if the source is connected at a higher potential than that of the bulk (i.e. 0), the threshold voltage of the MOSFET will
The intrinsic carrier concentration of silicon sample at 300 K is . If after doping, the number of majority carriers is , the minority carrier density is
A particular green LED emits light of wavelength 5490 . The energy bandgap of the semiconductor material used there is (Plank's constant = )
At 300 K, for a diode current of 1 mA, a certain germanium diode requires a forward bias of 0.1435 V, whereas a certain silicon diode requires a forward bias of 0.718 V. Under the conditions state abo
If P is Passivation, Q is n -well implant, R is metallization and S is source/drain diffusion, then the order in which they are carried out in a standard n - well CMOS fabrication process, is
When the gate-to-source voltage ( ) of a MOSFET with threshold voltage of 400 mV, working in saturation is 900 mV, the drain current is observed to be 1 mA. Neglecting the channel width modulation eff
The current flowing through the resistance R in the circuit in the figure has the form where P is
A source of angular frequency 1 rad/sec has a source impedance consisting of 1 resistance in series with 1 H inductance. The load that will obtain the maximum power transfer is
An input voltage is applied to a series combination of resistance R = 1 and an inductance L = 1 H. The resulting steady-state current i(t) in ampere is
The minimum number of equations required to analyze the circuit shown in the figure is
The impedance parameters and of the two-port network in the figure are
The differential equation for the current i(t) in the circuit of the figure is
Assume that the switch S is in position 1 for a long time and thrown to position 2 at t = 0. and are the Laplace transforms of and respectively. The equations for the loop currents and for the circuit
The driving point impedance Z(s) of a network has the pole-zero locations as shown in the figure. If Z(0) = 3, then Z(s) is
An ideal sawtooth voltages waveform of frequency of 500 Hz and amplitude 3 V is generated by charging a capacitor of 2 in every cycle. The charging requires
A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q=100. If each of R, L and C is doubled from its original value, the new Q of the circuit is
Twelve 1 resistance are used as edges to form a cube. The resistance between two diagonally opposite corners of the cube is
Let P be linearity, Q be time-invariance, R be causality and S be stability. A discrete time system has the input-output relationship, where x(n) is the input and y(n) is the output. The above system
Let x(t) = 2 cos (800 ) + cos (1400 t). x(t) is sampled with the rectangular pulse train shown in the figure. The only spectral components (in kHz) present in the sampled signal in the frequency range
Let x(t) be the input to a linear, time-invariant system. The required output is 4x(t-2). The transfer function of the system should be
A sequence x(n) with the z-transform is applied as an input to a linear, time-invariant system with the impulse response where The output at n = 4 is
The Fourier series expansion of a real periodic signal with fundamental frequency is given by . It is given that . Then is
The Laplace transform of i(t) is given by At The value of i(t) tends to
The system under consideration is an RC low-pass filter (RC-LPF) with R = 1 k and C = 1.0 F. Let be the group delay function of the given RC-LPF and = 100 Hz. Then in ms, is